The company will buy about 8,000 work vans or technician trucks that run on compressed natural gas over five years -- to be built by Ford.

Natural gas is cheaper, cleaner and we have plenty of it here domestically, Stephenson said in comments prepared for delivery to the meeting.

AT&T also plans to replace 7,100 other vehicles with hybrids and other advanced technology power systems over 10 years.

The hybrids will include a combination of gas-electric and plug-ins, and the trial includes mostly those made by Ford, with some from Toyota Motor Corp, according to Tim Harden, president of supply chain at the company.

T. Boone Pickens, a Texas billionaire oilman who has promoted the use of natural gas, praised AT&T's actions. In a statement, Pickens said it was a demonstration of real American corporate leadership that will be good for their bottom line, the environment and the country.